Fiber-reinforced resin composition

Abstract

To provide a fiber-reinforced resin composition excellent in tensile modulus, tensile strength and impact strength without using a glass fiber, an organic filler and a high-density polyethylene.SOLUTION: The fiber-reinforced resin composition contains polypropylene as a base resin and cellulose fibers as reinforcing fibers. The fiber-reinforced resin composition contains an acid-modified elastomer and a maleic anhydride-modified polypropylene.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a fiber-reinforced resin composition. [Background technology]

[0002] Patent Document 1 discloses a fiber-reinforced polyolefin resin composition (hereinafter referred to as "resin composition") containing a polyolefin resin as a base resin and cellulose fibers as reinforcing fibers. Generally, the inclusion of cellulose fibers in a polyolefin resin results in a trade-off in that the impact strength of the resin composition decreases. Patent Document 1 aims to improve impact strength by including an acid-modified elastomer and high-density polyethylene in the resin composition. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-156073 Summary of the Invention [Problem to be solved by the invention]

[0004] The resin composition described in Patent Document 1 has room for improvement in terms of reducing the production cost. [Means for solving the problem]

[0005] A fiber-reinforced resin composition for solving the above problems is a fiber-reinforced resin composition containing polypropylene as a base resin and cellulose fiber as reinforcing fiber, and further containing an acid-modified elastomer and maleic anhydride-modified polypropylene. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is an SEM image of the resin composition of the example. DETAILED DESCRIPTION OF THE INVENTION

[0007] Hereinafter, one embodiment of the fiber reinforced resin composition (hereinafter referred to as resin composition) will be described. The resin composition includes polypropylene as a base resin, cellulose fibers as reinforcing fibers, an acid-modified elastomer, and maleic anhydride-modified polypropylene.

[0008] The fiber diameter of the cellulose fibers is preferably 10 μm or more and 30 μm or less, and the fiber length of the cellulose fibers is preferably 0.5 mm or more and 3 mm or less. The reinforcing fibers are preferably cellulose fibers derived from sorghum.

[0009] The mass proportion of cellulose fibers is preferably 5% or more and 60% or less. The mass proportion of the acid-modified elastomer is preferably 1% or more and 10% or less. The mass proportion of the maleic anhydride-modified polypropylene is preferably 1% or more and 10% or less.

[0010] Next, with reference to Table 1, examples of resin compositions and comparative examples 1 to 3 will be described.

[0011] [Table 1]

[0012] <Example> The base resin in the examples is polypropylene. As shown in Table 1, the mass proportions of the cellulose fiber, acid-modified elastomer, and maleic anhydride polypropylene in the resin composition of the example were 50%, 3%, and 3%, respectively. Although not shown in Table 1, the mass proportion of the polypropylene base resin was 44%.

[0013] The tensile modulus, tensile strength, flexural modulus and flexural strength of the resin composition of the example are 4,110 MPa, 52.0 MPa, 3,990 MPa and 79.0 MPa, respectively. The Charpy impact strength (23°C) of the resin composition of the example is 5.4 kJ / m 2 is.

[0014] <Comparative Example 1> The base resin of Comparative Example 1 is the same polypropylene as in the Examples. As shown in Table 1, the mass proportions of the cellulose fiber, acid-modified elastomer, and maleic anhydride polypropylene in the resin composition of Comparative Example 1 were 50%, 5%, and 0%, respectively. Although not shown in Table 1, the mass proportion of the polypropylene base resin was 45%.

[0015] The tensile modulus, tensile strength, flexural modulus, and flexural strength of the resin composition of Comparative Example 1 were 2,806 MPa, 45.0 MPa, 3,860 MPa, and 76.9 MPa, respectively. The Charpy impact strength (23°C) of the resin composition of Comparative Example 1 was 5.3 kJ / m 2 is.

[0016] <Comparative Example 2> The base resin of Comparative Example 2 is the same polypropylene as in the Examples. As shown in Table 1, the mass proportions of the cellulose fiber, acid-modified elastomer, and maleic anhydride polypropylene in the resin composition of Comparative Example 2 were 50%, 0%, and 5%, respectively. Although not shown in Table 1, the mass proportion of the polypropylene base resin was 45%.

[0017] The tensile modulus, tensile strength, flexural modulus, and flexural strength of the resin composition of Comparative Example 2 were 4,187 MPa, 46.7 MPa, 4,581 MPa, and 97.0 MPa, respectively. The Charpy impact strength (23°C) of the resin composition of Comparative Example 2 was 3.0 kJ / m 2 is.

[0018] <Comparative Example 3> The base resin of Comparative Example 3 is the same polypropylene as in the Examples. As shown in Table 1, the mass proportions of the cellulose fiber, acid-modified elastomer, and maleic anhydride polypropylene were 20%, 3%, and 3%, respectively, in the resin composition of Comparative Example 3. Although not shown in Table 1, the mass proportion of the polypropylene base resin was 74%.

[0019] The tensile modulus, tensile strength, flexural modulus, and flexural strength of the resin composition of Comparative Example 3 were 2,061 MPa, 35.4 MPa, 2,472 MPa, and 67.7 MPa, respectively. The Charpy impact strength (23°C) of the resin composition of Comparative Example 3 was 3.5 kJ / m 2 is.

[0020] <Operation of this embodiment> The resin composition of this example can increase the tensile modulus and tensile strength compared to the resin composition of Comparative Example 1 which does not contain maleic anhydride modified polypropylene.

[0021] Furthermore, the resin composition of this example has a higher Charpy impact strength than the resin composition of Comparative Example 2 which does not contain an acid-modified elastomer. FIG. 1 shows an SEM image of the resin composition of the example.

[0022] As shown in Figure 1, the acid-modified elastomer and maleic anhydride-modified polypropylene connect the cellulose fibers and the polypropylene, which is thought to be the reason why the resin compositions of the examples have high tensile modulus, tensile strength, and impact strength.

[0023] Furthermore, because the reinforcing fibers are natural cellulose fibers, there is no need to include organic fillers such as glass fibers or synthetic resin fillers. Maleic anhydride-modified polypropylene is also cheaper than high-density polyethylene.

[0024] <Effects of this embodiment> (1) The fiber-reinforced resin composition includes polypropylene as a base resin and cellulose fibers as reinforcing fibers, and also includes an acid-modified elastomer and maleic anhydride-modified polypropylene.

[0025] According to this configuration, the effects of the above embodiment are achieved, and a fiber-reinforced resin composition having excellent tensile modulus, tensile strength, and impact strength can be provided without using glass fiber, organic filler, or high-density polyethylene.

[0026] (2) The mass percentage of cellulose fiber is 5% or more and 60% or less, the mass percentage of acid-modified elastomer is 1% or more and 10% or less, and the mass percentage of maleic anhydride-modified polypropylene is 1% or more and 10% or less.

[0027] With this configuration, it is possible to achieve a high level of tensile modulus of elasticity, tensile strength, flexural modulus of elasticity, flexural strength, and impact strength. (3) The reinforcing fiber is a cellulose fiber derived from sorghum.

[0028] Sorghum is an annual grass similar to rice that can be cultivated on abandoned farmland. In addition to cellulose fiber, bioethanol can be extracted from sorghum. According to the above configuration, the reinforcing fibers are cellulose fibers derived from sorghum, which contributes to the development of environmentally friendly industries.

[0029] <Example of change> This embodiment can be modified as follows: This embodiment and the following modifications can be combined and implemented within the scope of technical compatibility.

[0030] The reinforcing fibers are not limited to sorghum-derived cellulose fibers, but may be cellulose fibers derived from other wood pulps. The mass proportion of cellulose fibers may be less than 5% or greater than 60%.

[0031] The resin composition only needs to contain an acid-modified elastomer, and the mass ratio of the acid-modified elastomer may be less than 1% or more than 10%. The resin composition only needs to contain maleic anhydride-modified polypropylene, and the mass ratio of the maleic anhydride-modified polypropylene may be less than 1% or more than 10%.

Claims

1. A fiber-reinforced resin composition comprising polypropylene as a base resin and cellulose fiber as a reinforcing fiber, an acid-modified elastomer; and maleic anhydride modified polypropylene, Fiber-reinforced resin composition.

2. The mass ratio of the cellulose fiber is 5% or more and 60% or less, the mass proportion of the acid-modified elastomer is 1% or more and 10% or less; The mass ratio of the maleic anhydride-modified polypropylene is 1% or more and 10% or less. The fiber-reinforced resin composition according to claim 1.

3. The reinforcing fiber is the cellulose fiber derived from sorghum, The fiber-reinforced resin composition according to claim 1 or claim 2.

Images